Variable condenser



Feb. l 1927 E. PICARD VARIABLE CONDENSER rFiled June 19, 1925 y u/e n far:

.30 of a plurality of metallic '45 knob Patented eb. '1,119217..

UNITED STATES nnuoNn nom,

VARIABLE conmmsnn.

Application led. June 19, 1925, Serial No. 38,253, `ana in France October` 4, 1924.

My invention relates to variable condensers v comprising stationary and movable plates whereof'the relative rotation will vary the operative surface of the condenser.

5 According to the invention, in addition to its rapid movement of rotation which is effected bymeans of a control knob or dial secured to the shaft, the movable or rotor plates maybe given very fine displacements,

l these being produced by the rotation of an armwhich is mounted at one endl with considerable friction upon the rotor and is connected at the otherend with a bell crank lever whose free end can be more or less `l shifted by a hand controlled screw. The pitch of the screw and the length of the lever arm may be suitably'chosen in order to ob-. tain a very slight movement of the rotor even for a considerable rotation of the screw knob. v

The appended drawings which are given by way o example show an embodiment of my said invention as applicable to an air condenser for radio telegraphy or telephony. Fig. 1 is a perspective view of the condenser. ,v Fig. 2 is an axial section thereof. In the said figures, 3 is the stationary member ofthe condenser which is composed lates in parallel disposition which are'maintained between two cheeks or end plates 4 and 5 consisting of insulation and spaced apart by the crosspieces 6.

L `Forwardly of ythe said stationaryvmember v isdisposed the shaft 7 ca ing the movable member or rotor 8 which li ewlseconsists of corresponding parallel 'metallic plates which by the rotation of the shaft 7 may be moved,

without contact, through thespaces between the" plates of the stationarymember. To effeet this the said shaft is mounted in bear ings rovided in the end plates 4 and 5 and has sposed upon its upper part the milled taine uponthe shaft 7 for instance--by/ a'v nut. The outer or free end of the arm 10 is pivoted at `13 to the short arm of a bellcrank lever 14 which is pivotedsu on an axle 15 carried by a strap or brac et that is ymounted on the upper plate The long arm of said lever terminates in a fork 16 which is engaged between the two shoulders 17 and 18 of a screw 19 engaging in a tapped hole inthe plate. 5 and having at the top a k,special button 20.

AA spring 21 which is attached at one end to one of the cross-pieces 6 and at the other to the arm 10, tends to move the rotor in a given direction and "obv'iates all effect of. *play in the joints; said spring may further i assure the electrical connection between'the lrotor and 'the cross-piece, which latter, as shown, will in such event comprise a. termi'- nal 26. i

The variable condenser according to my invention is operated in a very simple. manner. The dial knob 9 is turned in order to rotate the shaft 7, but without effect upon the arm 10, and this affords an approximate ,adjustment ofthe capacity of the condenser.

,'An accurate or fine adjustment is obtained by turning the button 20 of the screw 19 whose motion, 'which vcan be as slight as desired, will rock .the lever 14 about vits pivot and rovide for` a very slight rotatior? of the` axle and the rotor 8.

It is further to be noted that by a suitable choice `of the length of the arm 10 sind of the ratio @between the arms of the lever, 14, I

kmay obtain a, very slight rotation of the shaft 7 er revolution of the screw 19. l

The iction of the arm 10 between the washers 11 and 12 must be greater than the friction ofthe shaft 7 in its bearings. Fi 2 shows an arran mentwhich offers exce lent. results fort is purpose. At the' ends' of the shaft 7 are the two journals 21 and 22, respectively engaged. in the screwthreaded bearin 23 and 24 which -are screwed into the en plates 4, 5. The movement of the rsaid journals is limited by a tapered shoulder 25 engaging al corresponding tapered recess in the bearin 23 or 24. The contact between the` sai shoulder and. recess will also provide for an exact vertical adjustment of 100 te rotor. u .Obviously',` mysaid invention-is not lim-v X ited to the type of air condenser hereinbe- 'foreset fort but is ap licable` to .allzconldensers having a` mova' e element co-opeljatin with a station element. f T e invention is rt-her alplicablefnt only to vcondensate but alsol te' a great num ber of other apparatus in which itis desiredA Cand connected at the other end to said arm,

to obtain an accurate adjustment, Jand chieflyA for variometers. i Iclaim'as my invention:

i 1. A117nstrument comprising rotor and stator members, a' shaft whereon the rotor isimounte'dfa handle for rotating said shaft to effect coarse adjustment of the rotor, and a de`viee for effecting fine adjustment of the '10 rotor? said device embodying an -arm fricl tionally mounted on the rotor shaft, a bellcranklever having one end thereof pivoted to said arm, and an operating screw con .nected with the other end of the bell-crans .15 to rock the same and thereby turn said arm and shaft. f

' 2. An instrument 'comprising rotor nand stator members, a shaft whereon the rotor ismonnted, a' handle for rotating said shaft 20 t0 eect coarse adjustment of the rotor, and a device for effecting line adjustment of the motor: said devi e embodying an arm frictionally mounted on the rotor shaft, a rocking element provided at one end with a fork 25 Vand connected at theother end to said arm,

and an operating'screw engaged insaidforkto rock said element when turned and thereby turn said arm and shaft.

3. An instrument omprising rotor and 3d stator members, a shaft whereon the rotor ismounted, a handle for rotating said shaft to effect coars/e adjustment of the rotor, and

a device for eecting fine adjustment of the rotor: said device embodying an arm fric- 35 tionallymounted on the rotor shaft. a rock# .l ingelement provided at one end withafork and an operating screw having a pair of spaced shoulders between which the .membersof said fork Aareslidably engaged to roel: said element when turned and thereby turn Said arm and shaft.

4. An instrument comprising rotor and stator members, a-shaft whereon the rotor is mounted, a handle for rotating said shaft to effect coarse adjustment of the rotor, and i a device for effecting fine adjustment of the rotor: said device embodying an arm frictionallv mounted on the rotor shaft, a helli crank lever having one end thci'eof pivoted.

to said arm and provided atfits other end with a fork, and an operating screw having a pair of spaced shoulders between whichthe members of said fork are slidably engaged to rock said bell-crank when turned and thereby turn said arm and shaft.y

5. An instrument comprising rotor and stator members, a shaft' whereon the rotor Ais mounted, a handle for rotating said shaft to eect coarse adjustment of the rotor. a device for effecting fine adjustment of the ro'tor: .said device embodying an arm fric tionally mounted on the rotor shaft. a bell- -crank lever having one end thereof pivoted to said arm, and an o rating screw connected with the other end of the bell-crank to rock the same and thereby turn` said arm and shaft; and a return spring connected at opposite ends to"said\ arm and'to the stator. i

In testimony whereof I atiix my signature.

` 'EDMOND PICARD. 

